As you can't have a proper samurai showdown without absurd arterial spray and dismemberment, The Creative Assembly has released a new Total War: Shogun 2 downloadable content pack which amps up the bloodletting to the requisite level. If you'd rather be a sneaky ninja, though, the Hattori clan previously exclusive to the Shogun 2 Limited Edition is now sold separately.
For $1.59, the Blood Pack adds gruesome new animations and effects. Units can be decapitated or have their limbs severed, squirt blood when hit, get drenched in blood, splat on the ground, and generally make a lovely mess. The DLC actually has a higher rating than the base game, so you'll need to be a proper grown-up to buy it.
The $4.99 Hattori Clan Pack, meanwhile, lets you be the sneaky Hattori, described as "masters of the shadowy arts of assassination and bribery," in both single-player and multiplayer. It also packs a new battle scenario, based upon historical events, plus snazzy armor and an XP boost for your General's avatar.
The Creative Assembly is working on a standalone expansion for Shogun 2, Fall of the Samurai.